Have you been feeling blah? Have you been wondering if you have a B vitamin deficiency or if should take a B vitamin? Everyone seems to be on one, especially the methylated ones. For all you B-ginners, let’s dive in!
What are the Bs?
B vitamins are a group of eight vitamins that are crucial for health. They are essential for making energy, making blood cells, supporting nerve, heart, and muscle function, and the list goes on… B6 alone is estimated to interact with over 100 enzymes in our body! In essence, B vitamins are critical in hundreds, if not thousands, of enzymatic reactions in our body, and not having enough B vitamins can lead to serious health problems.
Do I have enough?
Symptoms may hint whether or not you have a B vitamin deficiency. While each B vitamin plays a specific role, B vitamin deficiencies often occur together and can cause some general symptoms such as:
- Fatigue and weakness.
- Skin problems, such as rashes and cracks at the corner of the mouth, especially with riboflavin and biotin deficiencies
- Poor nail and hair growth, especially with biotin deficiency.
- Anemia
- Mood changes
- Nerve problems like tingling, numbness, or burning sensations. These are particularly common with B6 and B12 deficiencies.
As these symptoms are vague, testing can help determine B vitamin adequacy.
- Direct measurements. We can measure blood levels of B vitamins, such as thiamine, riboflavin, B6, B12, and folate. These are useful to help detect severe deficiency or toxicity. However, vitamin levels do not necessarily correlate with the body’s functional use of the vitamin, and you have “normal” levels but still have insufficient function.
- Indirect measurements. There are different methods to determine how well your body is using B vitamins.
- Homocysteine. Homocysteine is an amino acid that can accumulate in the blood if there is a B vitamin deficiency. High homocysteine levels are a risk factor for health problems, including heart disease and stroke.
- Methylmalonic acid. This is a breakdown product of an amino acid, isoleucine, and accumulates when there is insufficient B12.
- Urine organic acids. Accumulations of specific metabolites found in the urine can indicate inadequate B vitamin function.
Who is at risk for a deficiency?
Many different groups of people may be at risk of a deficiency.
- Limited dietary intake. People who eat limited amounts of whole grains, fruits and vegetables, and protein may not get sufficient B vitamins.
- Vegans and strict vegetarians. As B12 naturally occurs only in animal products, diets limited to animal products may require additional B12 supplementation.
- Alcohol dependence. Alcohol may interfere with B vitamin absorption.
- Digestive disorders. Inflammation or destruction in the GI tract, such as can occur with colitis or Crohn’s disease, can lead to malabsorption of nutrients. As well, surgical procedures such as gastric bypass or small bowel resections can cause absorption issues.
- Pregnancy or lactation. Growing babies need B vitamins, and pregnant or lactating women need additional B vitamin support.
- Older adults. As with other things that decline with age, so does the absorption of all nutrients, including B vitamins.
- Genetic variations. Certain genetic variations can affect how you process your B vitamins. The most well-known is MTHFR gene mutations, which can alter how folate is activated in the body.
Methylation and MTHFR. Methylation is a complex process, and several genes and enzymes play a role. While MTHFR is the most widely known, several genes may affect your methylation. While this is more than we will dive into in this blog, I will briefly highlight MTHFR.
- MTHFR is an enzyme in the body that activates folate into methylfolate, which is needed for many body functions, including DNA synthesis, cell repair, amino acid metabolism, and the creation of neurotransmitters.
- MTHFR mutations are relatively common in specific populations. The two common MTHFR gene variants are:
- C677T: 20–40% of white and Hispanic individuals carry one copy (heterozygous), and 8–20% have two copies (homozygous).
- A1298C: This variant is less common, with only 7–12% of North American, European, and Australian populations carrying one copy (heterozygous). The prevalence is even less common among Hispanics and Asians.
- Heterozygous. Having one copy of one of the gene variants will reduce folate processing, more so with the C677T mutation than with the A1298C mutation. For most people, there is minimal impact on health, especially if you are eating a diet rich in folate. During times of increased stress on the body when the need for B vitamins is greater — illness, pregnancy, or lactation — additional folate and B vitamins may be beneficial.
- Homozygous or compound heterozygous. Those with two copies of the C677T gene (or, less commonly, the A1298C gene) are homozygous with an estimated reduced MTHFR activity of around 70%. In contrast, those with one copy of the C677T and one copy of the A1298C gene are compound heterozygotes, also with reduced enzyme activity levels, although to a lesser extent. In either case, the potential for health problems due to the mutation is higher than in heterozygotes. In these cases, your healthcare provider may:
- Monitor your homocysteine levels.
- Recommend additional folate and B vitamins, especially for women planning on pregnancy or for people with signs or symptoms of B vitamin deficiency.
If you suspect a B vitamin deficiency, please talk to your healthcare provider.
Can you have too much?
Yes, of certain ones.
It would be extremely unlikely to become toxic from the B vitamins you get from your food; food contains smaller quantities of B vitamins, and as B vitamins are water-soluble, excesses are eliminated through your urine. However, you can have too much of a good thing when you take your Bs in supplement form, particularly niacin (B3) and pyridoxine (B6), especially if you have chronic kidney disease.
- Niacin toxicity can cause skin flushing, itching, nausea, vomiting, liver damage, and high blood sugar. Generally, you must get at least 1500 mg/day, for which a standard B complex usually contains 20x less than this amount. Higher niacin doses may be used for patients with cholesterol issues, but this would be monitored under the care of a healthcare provider.
- B6 pyridoxine toxicity can cause symptoms very similar to B6 deficiency, such as numbness and tingling, and with continued intake of high doses, can lead to nerve damage. In general, these doses are 200 mg/day over some time.
Methylated vs unmethylated
Methylated B vitamins, also known as activated B vitamins, are forms of B vitamins (B6, folate, and B12) that have been converted to their active methylated form and are directly usable by the cells. While some patients may benefit from methylated B vitamins, such as those with known B vitamin deficiencies, MTHFR gene mutations, or digestive/absorptive issues, currently, there is limited research on the long-term effects of methylated B vitamins for the general population. For most people, unmethylated B vitamins are likely sufficient.
Before starting any supplement or vitamin, I highly recommend that you speak to your healthcare provider and do not exceed the recommended doses unless you are under the guidance of a healthcare professional.
Happy B-ing vital!
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About the Author:
Dr. Eri Shimizu is a board certified in Internal Medicine Doctor and certified through the Institutes of Functional Medicine. She earned a Bachelor of Science in Environmental Bioengineering from the University of Hawaii at Manoa and graduated summa cum laude from Creighton University Medical School. She completed her Internal Medicine residency at UCLA and worked at a Los Angeles county hospital. In 2012, she returned to Hawaii and served as a Hospitalist at Maui Memorial Medical Center. Maui is now home with her husband, two children, and a fighting fish named Rainbow.
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